Pop valve



y 21, 1940- c. A. CAMPBELL 2,201,363

P O P VALVE Filed Aug. 17, 1938 Inventor attorneys Pstent dMe 2 L194o A4 in 2,201,363;

UNITED STATES PATENT. OFFICE" POP VALVE Charles A. Campbell, Watertown,N. Y., assignor to The New York Air Brake Company, a corporation of NewJersey Application August 17, 1938, Serial No. 225,477

9 Claims. (Cl. 181-37) This invention relates to improvements in pop thebody 6. The spring seat also serves as a valves, that is, safety or blowdown valves havguide for stem 14. I a ing a sharp opening and closingcharacteristic. The main discharge ports in the body are indi- Theinvention is particularly designed for use cated at 15. A row of suchports extends around with an improved po'p valve described and claimedthe valve body. The valve is formed with reacin the application ofCampbell and Saiford, Serial tion shoulders as described in the aboveentitled No. 162,035, filed September 1, 1937, Patent No. applicationand is provided with through ports 2,165,611, dated July 11, 1939, andwill be illus- 16 which lead to the space above, i. e., the space tratedsimply for purpose of explanation as apbehind the valve. This space isvented mat- 10 plied to a valve of that particular form. No mosphere bya row of lateral ports ll, which 10 claims are herein made to theconstruction of the as explained in the prior application, are throtpopvalve mechanism per se. tled more or less to control the operativecharac Valves of the type above mentioned are comteristics of the valve,particularly as to rapid openmonly used on passenger brakes and torelieve ing and closing. Spring seat i2 is locked in posipressures whichoften are rather high. The valve tionby an acorn nut l8 which screws onthe 15 opens and closes suddenly and consequently is upper end of thespring seat and abuts the upper apt to be noisy, partly because of thesudden blasts end of the body 6. of air which it discharges and arrests,and partly The parts .so far described are described in because of ahammering action which sometimes detail and claimed in the priorapplication and occurs when the valve opens. while there are refinementsinvolved in the par- -10 Such valves are sensitive to derangement byacticular design of the valve and the reaction shoul-' cumulation ofdirt or dust in the discharge ports ders, those features are notinvolved in the presand by the entrance of dust through these ports entinventionand need not be here elaborated. with an attendant tendency ofthe valve to stick. In the Campbell and Safiord valve a throttling Thereis also a tendency of the acorn nut, which ring isthreaded on the valvebody and may be, 25

locks the spring seat. to jar loose. Hence conadjusted tothrottle moreor less the upper ports. siderable ,difllculty has been encountered inIt is locked by a check nut. Instead of using service. such'a ring andcheck nut, the present invention The present invention produces acombined provides ,a sleeve l9 with a pendant skirt 2|muiller.protecting skirt and port adjusting means, extending downwardfrom the sleeve to a point '30 which, together with a buffer forlimiting openbelow the ports .15. v This sleeve: may be adjusted ingmovement of the valve stem, secures ceron the body 6 to. throttle ports.ll more or less, tainty of action, freedom from clogging, and and whenadjusted is locked in position by the muliling of the blast and othernoises produced clamping screw 22'which is threaded into a lugby theopening and closing of the valve. 20 on one side of the sleeve l9 andserves to 35 Referring to the accompanying drawing: close a saw kerf 23and thus lock the sleeve on. Fig. 1 is an axial section through thevalve. the threaded body; Thehead of the screw 22 n Fig. 2 is a viewlooking at the top or end of the engages a selected one of a series offlutes 24 valve of the present invention. formed on the lowermargin ofthe acorn nut" 40 Referring, flfst to Fig 1 5 represents t body I8. Thusthe screw 22 looks the sleeve l9 and 40 of the valve which is pipethreaded at l for Skirt at t S9rme time locks the ac'om attachment tothe portwhose discharge is to nut l8 so that-a'single locking means ssufiicient be controlled. Slidably'mounted in the body 6 alladlustmfmtsis the combined valve and piston 8 whose form .The skirt 2|has an internal shoulder 25, and is clearly shown in the drawing. Thisvalve rethe body s.has an external Shoulder This cipmcates within thebody and seats at a to shoulder 21 is usually above the hexagonal wrenchI duce the desired seal It is urged toward its gg onlthe body g i as-houlder is an annu ar spacer s ape in crossseat by a coiledcompresslon spring whlch section and projecting upward through the skirtreacts at its upper against an adlustable so that its vertical flange iswithin, and spaced 50 p i seat I2 threaded m the body 6 and reacts from,the skirt 2|. An annular felt filter ring at s lower end agamsl? theflange at the 29 is confined between two foraminous plates 3| lower endof the thrust stem 14. The stress of and 32, The lower plate 3i rests onthe fiange the spring H is adjustable by turning the spring of thespacer 28 and the upper plate is positioned seat 12 which is threaded inthe upper end of by th shoulder 25 within the skirt-2|. Thus the 5sfilter is sustained within the skirt above the ports i5 and below theports [1. It muflles the flow from ports I! because this flow must passdownward through the filter. It muflies the flow through the ports I5because this fiow must turn upward within the member 28, pass throughthe filter, and then fiow downward between the member 28 and the skirt2|.

The stem I4 is counter-bored at its upper end to receive stem 33 whichcarries the stop flange 34.- The flange 34 is large enough to engage atits margin with an annular rubber buffer 35 which is sprung into anundercut groove within the top of the acorn nut. When the valve popsopen sharply, the stop flange 34 will engage the buffer 35 and preventmechanical noise such as might otherwise result from sudden arrest ofthe valve stem.

The opening and closing characteristics of the valve are varied byscrewing the sleeve l9 up and down on the body. Loading of the valve isadjusted by screwing the spring seat I! more or less into the body.After the desired adjustments have been made the acorn nut I8 is screweddown to lock the spring seat. Then the screw 22 is inserted in the holeformed in the lug 20 to receive it. Only a slight angular displacementof the sleeve i9 is required to permit the head to enter one of theflutes in the acorn nut l8. Consequently, the acorn nut locks the springseat and the screw 22 locks the adjusting sleeve and the acorn nut bothat once.

In adjusting the sleeve l9 to vary the throttling of the upper ports H,the felt filter ring 29 is compressed more or less but is ofsufliciently yielding character to permit the necessary adjustment.

The proposed construction affords the same facilities for adjustment aswas had by the prior art structure with the additional possibility oflocking all the adjustments when they are made by the insertion of asingle screw. The sleeve IS with its pendant skirt and the filterstructure housed within that skirt protect all the lateral ports in thebody 6 from mud, snow and dust. The filter ring 29 muiiles discharge andthe spring buffer arrests the opening movement of the valve withoutnoisy shock. Thus accurate and quiet operation of the valve is assuredat all times. The valve is rendered substantially silent in operationwithout any impairment of its sharp opening and closing characteristics.because the filter has suflicient capacity to eliminate disturbing backpressure efi'ects.

While a particular and the preferred embodiment of the invention hasbeen described in considerable detail, this is intended to beillustrative rather than limiting. Modifications within the scope ,ofthe claims are contemplated.

What is claimed is:

1. In a popvalve, the combination of a body having lateral ports; avalve; a spring forseating said valve; afspring seat adjustably threadedin said body to stress said spring; a jamb nut for locking saidseat inadjusted positions; a port throttling member encircling said body andshiftably mounted thereon to throttle variably said lateral ports;clamping means, including a screw for locking the last named member inadjusted positions; and means on the jamb nut engaged by. said screwwhereby the screw, when set up to lock said throttling member, alsolocks the jamb nut.

2. The combination defined in claim 1 in which the throttling member isthreaded on the body and transversely slotted at one side,and the screwacts to close said slot and thereby lock the mem ber by frictionalengagement of the threads.

3. The combination of a pop valve having a body and a spring-seatedvalve, the body having lateral ports which if throttled afl'ect theoperating characteristics of the valve; a member encircling said bodyand shiftably mounted thereon to throttle variably said ports; means forclamping said encircling member in adjusted positions on said body; askirt carried by said member, spaced from the body and overlying saidports; and a discharge mufiiing and dust excluding filter mass mountedin the interval between said skirt and body.

4. The combination of a pop valve having a. body and a spring seatedvalve, the body having two rows of lateral ports, namely, a row ofcontrol ports which if throttled vary the operative characteristics ofthe valve, and a row of discharge ports; a member encircling said bodyand shiftably mounted thereon to throttle said ports in the desireddegree; means for clamping said member in adjused positions on saidbody; a skirt carried by said member spaced from the body and overlyingboth rows of ports; a filter mass mounted between said rows of ports inthe interval between said body and skirt; and means constrainingdischarge from both rows of ports to pass througmsaid filter mass.

5. The combination of a pop valve having a body and a springseatedvalve, the body having two rows of lateraljports, namely, a row ofcontrol ports which if throttled vary the operative characteristics ofthe valve, and a row of discharge ports; a member encircling said bodyand shiftably mounted thereon to throttle said ports in the desireddegree; a skirt carried by said member spaced from the body andoverlying both rows of ports; a removable filter element comprising afelt ring and a pair of foraminous confining rings between which thefelt ring is interleaved, said element filling the space within saidskirt for a portion of the interval between said rows of ports; meanscomprising a shoulder for sustaining the upper confining ring below theupper row of ports; and a deflector ring supported by the body andarranged to support the lower confining ring above the lower row ofports and to direct discharging fluid through the filter.

6. The combination with the structure of claim 5 of an adjustable seatfor the valve spring; a jamb nut for locking said seat; and a singlelocking means adapted to clamp said encircling member on said body andsimultaneously to engage said jamb nut and prevent releasing motionthereof.

7. A pop valve comprising in combination a body; a valve member slidablymounted therein; a spring for urging said valve in a closing direc tion;a spring seat threaded into the end of said body and adjustable to varythe stress on said spring; a cap nut for locking said spring seat in itsadjusted position; a sleeve surrounding said body; means for lockingsaid sleeve to said body; and means, associated with the last namedmeans, for locking said cap nut to said sleeve.

8. A pop valve comprising in combination a body; a valve member slidablymounted therein; a spring for urging said valve in a closing direction;a spring seat threaded into the end of said body and adjustable to varythe stress on said spring; a cap nut for locking said spring seat in itsadjusted position; a buffer mounted in said cap nut and arranged toarrest the opening move- 9. A pop valve comprising in combination abody; a valve member slidably mounted therein; a spring for urging saidvalve in a closing direction; a spring seat threaded into the end ofsaid body and adjustable to 'vary the stress on said in spring; a capnut for locking said spring seat in its adjusted position; a sleevesurrounding said body; means for locking said sleeve to said body;means, associated with the last named means, for locking said cap nut tosaid sleeve; and a filter body mounted within said sleeve and betweenthe sleeve and the body, said filter being retained by the sleeve andserving to protect the discharge ports of the valve.

CHARLES A. CAIIPBELL

